Here's an easy way to know how to name a new command page in the wiki. You just use the "What's This?" tool in FreeCAD and click on the icon for the command. The FreeCAD User Manual opens, and if the page does not exist, it gives the link to the page it's looking for. The name is after qthelp://org.freecad.usermanual/doc/
, without the .html file extension.
The interface of the manual in the video below is in French, it says "The page could not be found".
To fill a command page, you can use the GuiCommand model
page, there's a Selectable block section at the bottom that you simply copy-paste in a new page and then edit to your needs.